Writing instrument



FIG. 1 is a perspective view of a writing instrument according to the present invention;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top end view thereof; and,

FIG. 7 is a bottom end view thereof. 

What is claimed is the ornamental design for a writing instrument, as shown and described. 